Scales of the above described type are particularly useful when components of a mixture are to be measured successively and the operator of the scale wishes to know how much of the available weight range has been used up or is still available.
Earlier systems provided indicator instruments separate from the digital display of the scale. Later, the indicator instruments were displaced by displays utilizing light emitting diodes. Subsequently, it was decided that the display of the available weight range could also be digital display. In order that the same display could be used both for net weight and the available weight range, a separate operator-controlled element was provided which could call out the available weight range number for display, that is would switch the display so that the available weight range number would be displayed instead of the net weight.